Photo Credit: Mr. Suphachai Praserdumrongchai

The following is a summary of “Integration and Application of Radiologic Patterns From Clinical Practice Guidelines on Idiopathic Pulmonary Fibrosis and Fibrotic Hypersensitivity Pneumonitis,” published in the December 2023  issue of Pulmonology by Marinescu, et al.

Clinical practice guidelines do not specify whether or how to apply these approaches concurrently within a single patient; instead, they define the radiologic features of fibrotic hypersensitivity pneumonitis (fHP) and usual interstitial pneumonia (UIP) separately. What difficulties are associated with mentioned patterns that need to be reevaluated in future guidelines? How can they combine guideline-defined radiologic patterns to identify interstitial lung disease (ILD)? In a standardized multidisciplinary discussion, patients from the Registry for Pulmonary Fibrosis had a thorough reevaluation. 

For a study, researchers sought to determine clinical data, assess CT scan characteristics, and assign guidelines-defined patterns. The radiologist and an ILD doctor then received clinical data, and together, they arrived at the leading diagnosis.

Idiopathic pulmonary fibrosis (IPF) accounted for 26% of the clinical-radiologic diagnoses in 1,593 patients, followed by fHP in 12%, connective tissue disease-associated ILD (CTD-ILD) in 34%, idiopathic pneumonia with autoimmune characteristics in 12%, and unclassifiable ILD in 10% of cases. In 66% of patients, typical and probable UIP patterns were correspondingly associated with an IPF diagnosis. While compatible fHP was vague and linked to CTD-ILD or IPAF in 48% of patients, typical fHP pattern correlated with a fHP clinical diagnosis in 65% of individuals. No trend excluded CTD-ILD. A significant characteristic that broadly distinguished compatible and typical fHP from other patterns on expiratory imaging was gas trapping, which affected more than 5% of the lung parenchyma (sensitivity, 0.77; specificity, 0.91).

It is possible to tackle guideline-defined UIP and fHP patterns in an integrated manner.

This encourages gas trapping at >5% as a crucial branch point. Although sometimes confused with CTD-ILD, typical or probable UIP, and characteristic fHP patterns offer moderate predictive values for a corresponding diagnosis of IPF and fHP; compatible fHP is generic.

Source: sciencedirect.com/science/article/abs/pii/S0012369223011066